1. Field of the Invention
The present invention is directed to a dental x-ray diagnostics installation for producing panorama tomograms of the jaw of a patient, and in particular to such an installation wherein the radiation intensity is measured by clocked CCD sensors which are operated at a clock frequency to simulate a moving x-ray film.
2. Related Patent and Application
A dental x-ray diagnostics installation for producing panorama tomograms of the jaw of a patient, wherein the moving x-ray film used in previous installations of this type is replaced by a clocked CCD sensor arrangement operated to simulate the moving film, is disclosed in U.S. Pat. No. 4,823,369. The details of operation of the CCD sensor are disclosed in U.S. Pat. No. 4,878,234, and which is assigned to the same assignee as the present application.
The dental x-ray installation disclosed in the above differs from conventional panorama tomogram exposure equipment in that the x-ray film, which is moved behind the secondary diaphragm in conventional systems, is replaced by a stationary CCD sensor arrangement which is driven with a clock generator so that the charge images which are obtained are entered into a storage zone at a clock frequency to simulate the same speed at which the conventional x-ray film is moved relative to the secondary diaphragm. The charge images are then clocked out line-by-line by a shift register. The clock frequency f.sub.T is selected according to the relationship: EQU f.sub.T =v/(n.sub.x .multidot.a)
wherein v is the conventional film speed, n.sub.x is the imaging relationship of the image-transmitting system, and a is the line spacing.